Ethylene polar copolymerization reactor

Abstract

The present invention provides an ethylene polar copolymerization reactor, which comprises: a cylinder body, the cylinder body comprises an upper cover and a kettle body, and an internal member arranged in the cylinder body, and the internal member comprises a guide cylinder and a stirring device positioned in the guide cylinder; the stirring device comprises a stirring shaft, a stirring paddle and a stirring motor, the stirring paddle is a composite paddle consisting of a bottom paddle and a plurality of stages of non-bottom paddles or upper-layer paddles, the stirring paddle is mounted on the stirring shaft, the upper end of the stirring shaft penetrates through the upper cover and is connected with the stirring motor, and the lower end of the stirring shaft is fixed on the lower circular end socket through a rotating bearing; wherein the stirring shaft is of a hollow structure below the bottom paddle, the paddle of the bottom paddle is also of a hollow structure, the stirring shaft and the paddle are communicated with each other, the hollow structure of the stirring shaft is communicated with the outer pipeline of the kettle body through a pipeline, and a heat conduction medium is placed in the stirring shaft and the paddle; ethylene polar copolymerization can be achieved under the conditions that the pressure is smaller than or equal to 10 MPa and the temperature is smaller than or equal to 150 DEG C, the kettle sticking rate is smaller than or equal to 5%, the system viscosity can be regulated and controlled between 0 cP and 5000 cP, and ethylene polar copolymerization products with different properties can be produced in the same reactor.

Description

Technical Field

[0001] The invention relates to a reactor, in particular to an ethylene polar copolymerization reactor, in particular to a reactor capable of realizing ethylene polar copolymerization under low pressure conditions. Background Art

[0002] At present, there are two main ways to produce ethylene polar copolymer products in industry. One is high-pressure free radical polymerization technology, which uses kettle reactors or tubular reactors to complete the reaction under harsh conditions of 150MPa and above 150℃, and the reactants are discharged in a molten state at 150℃. This method has high equipment cost, complex structure, and the product is a random polymer; the other is post-functionalization technology, such as grafting or blending. Radiation grafting requires special equipment. Although blending equipment is simple, it consumes a lot of energy. The ethylene polar copolymer products obtained by these two methods cannot adjust the content of polar monomers in the polymer as needed. Therefore, the prior art has turned its attention to the coordination polymerization technology using late transition metal catalysts, which can achieve copolymerization of olefins and polar monomers under relatively mild conditions. However, it is found in research that the coordination polymerization using late transition metal catalysts also has disadvantages: its high initial activity causes the generated polymer to aggregate and agglomerate, which is not conducive to the subsequent reaction; under certain conditions, part of the generated polymer is easy to adhere to the inner wall and internal components of the reactor, affecting the heat transfer effect and subsequent reactions. When the concentration of polar monomers (such as methyl acrylate) in the reaction system is high, the ester content in the obtained product is also increased accordingly. Under the reaction conditions, the reaction system as a whole may be in a relatively viscous state. These all require the reactor to have strong adaptability to ensure that the coordination polymerization can proceed smoothly.

[0003] At present, in addition to polishing and grinding the inside of the reactor to increase the smoothness and reduce the sticking of the reactor, the existing technology mainly adopts the method of coating the inner wall and internal components of the reactor with anti-adhesion agents to solve the problem of sticking of the reactor; some existing patents disclose the technology of using anti-adhesion agents, but there are disadvantages that the coating is easy to fall off and the service life is limited, and the coating material cannot interfere with the polymerization, so the range of materials selected is limited. For high-viscosity polymerization systems, the existing technology mainly designs reactor types suitable for high-viscosity systems to meet the needs; some existing patents disclose a series of polymerization reactors suitable for high-viscosity systems. These technologies start from two aspects, one is innovation in reactor type, and the other is innovation in stirring systems suitable for high-viscosity systems, but it is impossible to determine whether these reactors are suitable for ethylene and acrylate monomer copolymerization reaction systems. In addition, the prior art also aims to improve gas-phase mass transfer by improving the stirring system; some existing patents disclose technical solutions for meeting mass transfer or heat transfer requirements by setting a cavity inside the stirring paddle, but the solutions are highly targeted and will bring new problems while meeting the requirements, such as loss of mechanical strength of the stirring shaft; as mentioned above, there is no special reactor disclosed that matches the polar copolymerization of ethylene, especially the coordination copolymerization of ethylene and acrylic acid ester monomers, can solve the problem of kettle sticking from an engineering perspective, and can adapt to medium and low viscosity reaction systems of 0-5000cP.

[0004] In summary, the coordination polymerization of ethylene and polar monomers under mild conditions of ≤10MPa and ≤150℃ is a new technology studied in recent years, which has the advantage that the product structure can be adjusted as needed; however, its own reaction characteristics may lead to the production of some oligomers, even agglomeration or sticking in the reactor during the polymerization process; in addition, when the ester content is high, the product may be in a more viscous state under the reaction conditions, all of which require the reactor to have strong adaptability. Summary of the invention

[0005] In view of the shortcomings of the above-mentioned prior art, the present invention provides an ethylene polar copolymerization reactor, the purpose of which is to develop a reactor that can achieve ethylene polar copolymerization under conditions of ≤10MPa and ≤150°C, with a sticking rate of ≤5% and a system viscosity that can be adjusted between 0-5000cP, so as to meet the need of producing ethylene polar copolymer products with different properties in the same reactor.

[0006] In order to achieve the above object, the present invention provides an ethylene polar copolymerization reactor, the copolymerization reactor comprising:

[0007] The cylinder body comprises an upper cover and a kettle body, and the kettle body consists of an upper cylindrical hollow body, a lower circular head and an external jacket;

[0008] and an internal component disposed in the cylinder, the internal component comprising a flow guide cylinder and a stirring device located in the flow guide cylinder;

[0009] The stirring device comprises a stirring shaft, a stirring paddle and a stirring motor, wherein the stirring paddle is a composite paddle consisting of a bottom paddle and a plurality of non-bottom paddles or upper paddles, the stirring paddle is mounted on the stirring shaft, the upper end of the stirring shaft passes through the upper cover and is connected to the stirring motor, and the lower end of the stirring shaft is fixed to the lower circular head through a rotating bearing;

[0010] Among them, the stirring shaft has a hollow structure below the bottom paddle, and the blades of the bottom paddle are also hollow structures, and the two are connected to each other. The hollow structure of the stirring shaft is connected to the external pipe of the kettle body through a pipe, and a heat conduction medium is placed in the stirring shaft and the blades.

[0011] In some embodiments, the stirring shaft is located on the line connecting the center of the upper cover and the center of the kettle head;

[0012] The blades of each level are arranged at equal intervals along the stirring shaft and are evenly distributed around the circumference, and there is a certain gap between the edge of the blade and the guide tube;

[0013] The bottom paddle of the stirring paddle adopts a radial flow type blade, and the paddles of each stage except the bottom paddle adopt axial flow type blades.

[0014] In some embodiments, the internal component also includes a baffle, one side of which is connected to the wall of the kettle body, the baffle is an internal hollow structure, the baffle and the external jacket are connected to each other through a pipe on the wall of the kettle body, and a heat transfer medium is placed in the hollow structure.

[0015] In some of the embodiments, the baffle is a rectangular structure with a trapezoidal cross-section and a hollow interior, and forms an angle of 0-10° clockwise with the axis of the stirring shaft.

[0016] In some of the embodiments, a plurality of inner baffles are provided on the inner wall of the guide tube. The inner baffles are rectangular structures, forming a counterclockwise angle of 0-5° with the stirring shaft, and the length does not exceed the upper and lower edges of the guide tube. The inner baffles are arranged continuously and the width at the paddle blades of the stirring paddle is not greater than the gap between the paddle blades and the inner wall of the guide tube.

[0017] In some of the embodiments, the guide tube is a cylindrical solid structure with a certain thickness, and the guide tube is a trapezoidal cylindrical structure with a lower opening larger than an upper opening, and an angle formed by the trapezoidal side and the axis of the stirring shaft is 0-5°.

[0018] In some embodiments, the internal component further includes a heat exchange tube, the heat exchange tube is located between the guide tube and the kettle body, and the baffle can serve as a support for the heat exchange tube.

[0019] In some embodiments, the heat exchange tube is a combined tube bundle structure, consisting of a first main pipe and a second main pipe entering and exiting the reactor body, the first main pipe and the second main pipe are further divided into multiple groups of branch pipes, and the branch pipes are spirally coiled in the reactor body.

[0020] In some embodiments, the internal component further includes a gas distributor, which is located below the heat exchange tube, and the gas distributor is introduced into the kettle body through the lower circular head of the kettle body, and the gas distributor includes a plurality of straight tubes introduced into the kettle and a tube end distribution head;

[0021] The pipe end distribution head of the gas distributor is linear and is on the same horizontal line as the bottom propeller, and the angle between the distribution head and the horizontal edge of the bottom propeller blade is 0-5°.

[0022] In some embodiments, the kettle body is provided with cold medium inlet and outlet pipes and hot medium inlet and outlet pipes connected to the heat exchange tube; the lower circular head is provided with a liquid material discharge pipe;

[0023] The outer jacket is provided with a cold medium inlet and outlet pipe opening and a hot medium inlet and outlet pipe opening, and a heat transfer medium is provided on the outer wall of the inner kettle of the outer jacket;

[0024] The upper cover is provided with a liquid material feed pipe, a gas material feed pipe and a vent pipe; the kettle body is also provided with a plurality of thermocouple tubes for containing temperature measuring thermocouples.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The adhesion of polymers to the walls and internal components of the reactor has always been a difficult problem that needs to be solved urgently in the field. The present invention designs the stirring shaft and the bottom paddle blades below the bottom paddle as a centrally controlled and internally connected structure, and places a heat transfer medium (such as an electric heating plate, heat transfer oil, etc.) in the stirring shaft and the blades. When necessary, the necessary energy can be output to the bonding surface where the polymer and the blade are adhered by heating with the heat transfer medium, thereby increasing the fluidity of the polymer, reducing its viscosity, and promoting the shedding of the adhered polymer, effectively solving the problem that the generated polymer is easy to adhere to the bottom paddle. The measured adhesion rate is ≤5%.

[0027] The present invention adopts a kettle wall baffle with a specific shape and internal structure, and places a heat conduction medium (such as an electric heating plate) or introduces a hot fluid medium in the hollow structure of the kettle wall baffle to ensure that the baffle can maintain a relatively high temperature in a relatively short time, thereby weakening the contact interaction force between the adhered polymer and the metal wall, improving the activity of the adhered polymer in the system, and allowing the adhered polymer lumps or particles to detach from the baffle as soon as possible, thereby minimizing the agglomeration and adhesion of the polymer at the inner wall baffle of the kettle. If necessary, the adhered polymer can be heated by a strong heat conduction medium to promote the shedding of the adhered polymer, effectively solving the adhesion problem of the generated polymer on the baffle, and the measured adhesion rate is ≤5%.

[0028] The present invention ensures the mass transfer requirements of the system by selecting the best blade shape and combination, setting the baffles in the guide tube, and reasonably selecting the arrangement of the guide tube and the baffles, and objectively plays a role in ensuring the uniform dispersion of the polymer in the system to the greatest extent.

[0029] The present invention optimizes the combined arrangement of heat exchange tubes in the kettle and other comprehensive measures to achieve a heat removal margin of more than 135% in the reactor. By sacrificing the heat removal margin, it is ensured that the reactor can adapt to the need of regulating the viscosity of the system between 0 and 5000 cP, and can meet the need of producing ethylene polar copolymer products with different properties in the same reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 It is a schematic cross-sectional diagram of the overall structure of an ethylene polar copolymerization reactor shown in an embodiment of the present invention;

[0032] Figure 2 It is a partial structural schematic diagram of an ethylene polar copolymerization reactor shown in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the lower structure of the stirring shaft in the ethylene polar copolymerization reactor shown in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the structure of the inner wall baffle of the kettle body shown in an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the structure of a heat exchange tube in an ethylene polar copolymerization reactor shown in an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of the structure of a gas distribution head according to an embodiment of the present invention;

[0037] in:

[0038] 1-Cylinder;

[0039] 11- upper cover;

[0040] 111-liquid material feeding pipe;

[0041] 112-gas material feeding pipe;

[0042] 12- kettle body;

[0043] 121-upper cylindrical hollow body;

[0044] 122-lower circular head;

[0045] 1221-liquid material discharge pipe;

[0046] 123-external jacket;

[0047] 1231-cold medium inlet and outlet;

[0048] 1232-heat medium inlet and outlet pipes;

[0049] 13-thermocouple tube;

[0050] 2-Internal components;

[0051] 21- flow guide tube;

[0052] 211- stirring shaft;

[0053] 212- stirring paddle;

[0054] 213- stirring motor;

[0055] 22- baffle;

[0056] 23-inner baffle;

[0057] 24- heat exchange tube;

[0058] 241-First General Manager;

[0059] 242-Second General Manager;

[0060] 243-cold medium inlet and outlet pipes;

[0061] 244-heat medium inlet and outlet pipes;

[0062] 25-gas distributor;

[0063] 251-Pipe end distribution header. DETAILED DESCRIPTION

[0064] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments to further understand the purpose, solution and effect of the present invention, but it is not intended to limit the scope of protection of the claims attached to the present invention.

[0065] Certain words are used in the specification and subsequent claims to refer to specific components or parts. It should be understood by those of ordinary skill in the art that technical users or manufacturers may refer to the same component or part by different nouns or terms. This specification and subsequent claims do not use differences in names as a way to distinguish components or parts, but use differences in the functions of components or parts as the criteria for distinction. "Including" and "comprising" mentioned throughout the specification and subsequent claims are open-ended terms and should be interpreted as "including but not limited to". In addition, the word "connect" here includes any direct and indirect electrical connection means. Indirect electrical connection means include connection through other devices.

[0066] It should be noted that, in the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and "about", or "approximately", "substantially", "left and right" and the like indicating directions or positional relationships or parameters are all based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description content, and do not indicate or imply that the referred device or element must have a specific direction, specific size, or be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0067] In order to solve the problem of kettle sticking that may occur during the coordination polymerization of ethylene and acrylic ester monomers and meet the need to produce ethylene polar copolymer products with different properties in the same reactor, the embodiment of the present invention is committed to providing a special reactor that can achieve ethylene polar copolymerization under the conditions of ≤10MPa and ≤150°C, with a kettle sticking rate of ≤5% and a system viscosity that can be adjusted between 0-5000cP.

[0068] See also Figure 1-6An embodiment of the present invention discloses an ethylene polar copolymerization reactor, the copolymerization reactor comprising: a cylinder 1, the cylinder 1 comprising an upper cover 11 and a kettle 12, the kettle 12 comprising an upper cylindrical hollow body 121, a lower circular head 122 and an external jacket 123; the upper cover 11 is a circular entity with a certain thickness, and an internal component 2 is placed in the cylinder 1, the internal component 2 comprises a guide tube 21 and a stirring device located in the guide tube 21; the stirring device The stirring device comprises a stirring shaft 211, a stirring paddle 212 and a stirring motor 213. The stirring paddle 212 is a composite paddle consisting of a bottom paddle and a plurality of non-bottom paddles or upper paddles. The stirring paddle 212 is installed on the stirring shaft 211. The upper end of the stirring shaft 211 passes through the upper cover 11 and is connected to the stirring motor 213. The connection between the stirring shaft 211 and the driving device, i.e., the stirring motor 213, can adopt any existing mature technology; the lower end of the stirring shaft 211 is fixed on the lower circular head 122 through a rotating bearing;

[0069] Among them, the stirring shaft 211 has a hollow structure below the bottom paddle, and the blades of the bottom paddle are also hollow structures, and the two are connected to each other. The hollow structure of the stirring shaft 211 is connected to the external pipe of the kettle body 12 through a pipe, and a heat conduction medium is placed in the stirring shaft 211 and the blades.

[0070] That is, in this embodiment, the lower part of the stirring shaft 211 below the bottom paddle is a hollow structure and the hollow structure does not affect the mechanical strength of the stirring shaft 211, and the bottom paddle blades are also hollow structures and the hollow structure does not affect the mechanical strength of the blades. The two are interconnected, and the hollow structure of the stirring shaft 211 is connected to the pipeline outside the kettle through a pipeline, and a heat conduction medium (such as an electric heating plate, heat transfer oil, etc.) can be placed in the stirring shaft 211 and the blades.

[0071] In this embodiment, the stirring shaft 211 is located on the line connecting the center of the upper cover 11 and the center of the head of the kettle body 12; the blades of each stage are arranged at equal intervals along the stirring shaft 211 and are evenly distributed around the circumference, and there is a certain gap between the edge of the blade and the guide tube 21. Specifically, there is a gap of ≥5mm between the edge of the blade and the inner wall of the guide tube 21; the bottom paddle of the stirring paddle 212 adopts a blade with a radial flow type, such as a turbine paddle of a semi-elliptical tube; the paddles of each stage except the bottom paddle adopt an axial flow blade, such as an axial flow wide-blade wing-shaped paddle, and adopt a downward pressure operation mode.

[0072] In this embodiment, the internal component further includes a baffle 22, one side of which is connected to the wall of the kettle body 12, and the baffle 22 is a hollow structure. The baffle 22 and the external jacket 123 are connected to each other through a pipe on the kettle body wall, and a heat transfer medium (such as an electric heating plate or introducing the cold or hot medium in the jacket into the baffle) is placed in the hollow structure. The baffle 22 is a rectangular structure with a trapezoidal cross section and a hollow interior, has a certain thickness, and forms a clockwise angle of 0-10° with the axial direction of the stirring shaft 211.

[0073] In this embodiment, a plurality of inner baffles 23 are provided on the inner wall of the guide tube 21. The inner baffles 23 are rectangular in structure and form a counterclockwise angle of 0-5° with the stirring shaft 211. The length does not exceed the upper and lower edges of the guide tube 21. The inner baffles 23 are arranged continuously and the width at the blades of the stirring paddle 212 is not greater than the gap between the blades and the inner wall of the guide tube 21.

[0074] In this embodiment, the guide tube 21 is a cylindrical solid structure with a certain thickness. The guide tube 21 is a trapezoidal cylindrical structure with a lower opening larger than an upper opening. The angle formed by the trapezoidal side and the axis of the stirring shaft 211 is 0-5°.

[0075] In this embodiment, the inner component 2 further includes a heat exchange tube 24 . The heat exchange tube 24 is located between the guide tube 21 and the inner wall of the kettle body 12 . The baffle 22 can serve as a support for the heat exchange tube 24 .

[0076] In this embodiment, the heat exchange tube 24 is a combined tube bundle structure, which is composed of a first main pipe 241 and a second main pipe 242 entering and exiting the reactor body 12. The first main pipe 241 and the second main pipe 242 are further divided into a plurality of branch pipes, and the branch pipes are spirally coiled in the reactor body 12.

[0077] In this embodiment, the internal component 2 further includes a gas distributor 25, which is located below the heat exchange tube 24. The gas distributor 25 is introduced into the kettle body 12 through the lower circular head 122 of the kettle body 12. The gas distributor 25 includes a plurality of straight tubes introduced into the kettle and a tube end distribution head 251.

[0078] The pipe end distribution head 251 of the gas distributor 25 is linear and is on the same horizontal line as the bottom propeller, and the angle between the distribution head 251 and the horizontal edge of the bottom propeller blade is 0-5°.

[0079] In this embodiment, the kettle body 12 is provided with a cold medium inlet and outlet pipe port 243 and a hot medium inlet and outlet pipe port 244 connected to the heat exchange tube 24, and a plurality of temperature measuring devices are also provided in the kettle body 12; the lower circular head 122 is provided with a liquid material discharge pipe port 1221; the outer jacket 123 is provided with a cold medium inlet and outlet pipe port 1231 and a hot medium inlet and outlet pipe port 1232, and a heat transfer medium (such as a heating plate) is provided at the outer wall of the inner kettle of the outer jacket 123, and in addition, a plurality of mounting ears are also provided; the upper cover 11 is provided with a liquid material feed pipe 111, a gas material feed pipe 112 and a vent pipe, a pressure remote transmission facility, etc.; the kettle body 12 is also provided with a plurality of thermocouple tubes 13 for containing temperature measuring thermocouples.

[0080] The above ethylene polar copolymerization reactor disclosed in the embodiment of the present invention can realize ethylene polar copolymerization under the conditions of ≤10MPa and ≤150°C, with a kettle sticking rate of ≤5%, and the system viscosity can be regulated between 0-5000cP. It can better solve the agglomeration and kettle sticking problems that may occur in the coordination polymerization process and meet the needs of producing ethylene polar copolymer products with different properties in the same reactor.

[0081] In particular, the present invention also provides a method for copolymerizing ethylene with a polar monomer using the ethylene polar copolymerization reactor disclosed in the above embodiment, in particular a method for copolymerizing ethylene with methyl acrylate, specifically:

[0082] The copolymerization of ethylene and polar monomers, especially ethylene and methyl acrylate, is completed under the conditions of 1.0-10.0 MPa, 30-100°C, and 0.5-8 h using alkyl salicylaldehyde imine late transition metal complex or alkyl diimine late transition metal complex as catalyst precursor, alkyl aluminum compound and / or organic boron compound as activator, and at least one of toluene, hexane, etc. as solvent. The reactor is replaced with 0.1 MPa nitrogen three times to exhaust the air in the reactor. The reactor is heated to 150°C under a vacuum degree of -0.1 MPa, kept at a constant temperature for 2 hours, and then cooled to room temperature. The reactor is replaced with 0.1 MPa nitrogen three times again, and then the reactor is pressurized to 0.1 MPa with 0.1 MPa ethylene and replaced three times. At room temperature and in an ethylene atmosphere, the measured solid and liquid materials such as catalyst, solvent and polar monomer are added into the reactor through the liquid material feed pipe port on the upper cover of the reactor, and the filling coefficient of the reactor is maintained at 0.6. Start the stirring paddle, and make the reactor reach the set reaction temperature through the hot medium in the jacket outside the reactor. The reaction temperature is controlled to be constant within the desired range by adjusting the flow rate of the cold medium in the heat exchange tube in the reactor online. The temperature is monitored by the temperature measuring facilities inside the reactor and the signal required by the temperature controller is fed back. The temperature control accuracy is ±1°C. Ethylene is introduced to make the reactor reach the set reaction pressure and keep the pressure of the reactor constant. The instantaneous consumption flow rate and cumulative consumption flow rate of ethylene are measured by a mass flowmeter. After the reaction reaches the set time, stop stirring and release the ethylene pressure until the pressure gauge shows 0MPa. Add a terminator (such as alkyl alcohol) in an amount of 0.01% of the filling liquid volume to terminate the reaction. The reaction materials are discharged from the reactor through the liquid discharge port at the lower head of the reactor body to complete the subsequent work such as solid-liquid separation, polymer devolatilization, drying, weighing and analysis.

[0083] Source of raw materials and equipment: Ethylene, polymerization grade, purity 99.9%, produced by Daqing Branch of China National Petroleum Corporation.

[0084] Methyl acrylate, analytical grade, 98.5%, containing 0.05% MEHQ stabilizer, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0085] Methyl methacrylate, analytical grade, 98.5%, containing 0.05% MEHQ stabilizer, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0086] Toluene solution of methylaluminoxane, concentration 10%, provided by Huainan Kedi Chemical Technology Co., Ltd.

[0087] Toluene, analytical grade, 99.5%, was provided by Nanjing Chemical Reagent Co., Ltd.

[0088] Hexane, 98%, provided by Fushun Branch of PetroChina Co., Ltd.

[0089] In summary, the adhesion of polymers to the walls and internal components of the reactor has always been a difficult problem that needs to be solved urgently in this field. Adhesion refers to the process of one substance attaching to the surface of another substance. Adhesion requires energy from chemical and / or physical connections. When sufficient energy is applied, the physical connection is reversible. Previous studies have found that the polymer formed by the copolymerization of ethylene and acrylic acid ester monomers is a thermoplastic polymer. The ester group in the molecular structure enables it to combine with other substances through intermolecular forces and hydrogen bonds, making it have a certain degree of adhesion, especially easy to bond with metals or agglomerate with each other. During the polymerization process, when two polymer molecular chains contact the stirring paddle one after another, due to the obstruction of the stirring paddle, the contact opportunities between the molecular chains and the stirring paddle and / or between the two molecular chains are increased, which leads to the two molecular chains easily forming agglomerations and adhering to the stirring paddle. This is mainly a physical process; but as the temperature rises, its viscosity will gradually decrease, while the fluidity will gradually increase. The technical solution disclosed in the embodiment of the present invention is to design the stirring shaft and the bottom paddle blades below the bottom paddle as a hollow and internally connected structure, and place a heat conduction medium (such as an electric heating plate, heat transfer oil, etc.) in the stirring shaft and the blades. When necessary, the necessary energy can be output to the bonding surface where the polymer and the blades are adhered by heating with the heat conduction medium, thereby increasing the fluidity of the polymer, reducing its viscosity, and promoting the shedding of the adhered polymer, thereby effectively solving the problem that the generated polymer is easy to adhere to the bottom paddle, and the measured adhesion rate is ≤5%.

[0090] Furthermore, the baffle plays an important role in eliminating material vortexes and enhancing the mixing effect, but the characteristics of the copolymer of ethylene and acrylic ester monomers also make it easier for them to aggregate and adhere to the baffle. Especially when there is a certain temperature fluctuation on the kettle wall during the polymerization process or the polymerization is carried out under the condition of system viscosity ≥1000cP, the adhesion of the polymer at the baffle will increase significantly. Failure to clean it in time will seriously affect the mass transfer and heat transfer effects of the system and may even cause the polymerization to fail to proceed normally. According to the above principles, the technical solution disclosed in the embodiment of the present invention adopts a kettle wall baffle with a specific shape and internal structure, and places a heat conduction medium (such as an electric heating plate) or introduces a hot fluid medium in the hollow structure of the kettle wall baffle to ensure that the baffle can maintain a relatively high temperature in a relatively short time, thereby weakening the interaction force of the contact layer between the adhered polymer and the metal wall, improving the activity of the adhered polymer in the system, and allowing the adhered polymer lumps or particles to detach from the baffle as soon as possible, thereby minimizing the agglomeration and adhesion of the polymer at the inner wall baffle of the kettle. If necessary, the adhered polymer can be heated by a strong heat conduction medium to promote the shedding of the adhered polymer, thereby effectively solving the problem of adhesion of the generated polymer to the baffle, and the measured adhesion rate is ≤5%.

[0091] The technical solution disclosed in the embodiment of the present invention ensures the mass transfer requirements of the system by selecting the best blade shape and combination, setting the baffles in the guide tube, and reasonably selecting the arrangement of the guide tube and the baffles, and objectively also plays a role in maximally ensuring the uniform dispersion of the polymer in the system.

[0092] The technical solution disclosed in the embodiment of the present invention achieves a heat removal margin of more than 135% in the reactor by optimizing the combined arrangement of the heat exchange tubes in the kettle and other comprehensive measures. By sacrificing the heat removal margin, it is ensured that the reactor can adapt to the need of regulating the system viscosity between 0 and 5000 cP, and can meet the need of producing ethylene polar copolymer products with different properties in the same reactor.

[0093] Furthermore, the present invention provides the following specific embodiments:

[0094] Example 1

[0095] 100L ethylene polar copolymerization reactor and its effect in ethylene and methyl acrylate copolymerization experiments.

[0096] (1) 100L ethylene polar copolymerization reactor

[0097] A kettle-type stirred reactor comprises a cylinder 1 and an internal component 2. The volume of the reactor cavity is 100 L and the material is 304.

[0098] The cylinder 1 is composed of an upper cover 11 and a kettle body 12. The upper cover 11 is a cylindrical entity with a thickness of 130 mm. The kettle body 12 is composed of three parts: the kettle body 12, the lower circular head 122 and the external jacket 123. The cylindrical hollow body is 510 mm long, 400 mm in outer diameter and 12 mm in wall thickness. The jacket has a diameter of 500 mm and a wall thickness of 6 mm. The jacket is provided with a cold medium inlet and outlet pipe with a diameter of DN20. The lower circular head 122 is provided with a liquid material discharge pipe 1221 with a diameter of DN25. The jacket is provided with a cold medium inlet and outlet pipe with a diameter of DN20. The jacket is provided with a hot medium inlet and outlet pipe port 1232 with a diameter of DN20, and the hot medium inlet and outlet pipe is connected to the kettle wall baffle 22. In addition, 4 mounting ears are provided. The kettle upper cover 11 is provided with a liquid material feed pipe 111 with a diameter of DN25. The upper cover 11 of the kettle is provided with a gas material feed pipe 112 and a vent pipe, with a pipe diameter of DN14. The upper cover 11 is provided with a thermocouple tube 13 for containing a temperature measuring thermocouple, with a pipe diameter of DN20, a length of 135mm and extending deep into the kettle. The upper cover 11 is provided with a cold medium inlet and outlet pipe port 243 connected to the heat exchange pipe 24 in the kettle, with a pipe diameter of DN12.

[0099] The internal component 2 is composed of a stirring device, a heat exchange tube 24 , a baffle 22 and a gas distributor 25 .

[0100] The stirring device is composed of a stirring shaft 211, a stirring paddle 212 and auxiliary equipment (such as a stirring motor 213). The stirring paddle 212 is composed of three layers of paddles, including a bottom paddle, a first-level upper paddle and a second-level upper paddle. The diameter of the bottom paddle is 120 mm, the diameter of the first-level upper paddle and the second-level upper paddle is 180 mm, the paddle spacing is 130 mm, and the distance between the bottom paddle and the lower end of the lower head is 90 mm. The stirring shaft 211 is located on the line connecting the center of the upper cover 11 and the center of the head of the kettle body 12. The upper end of the stirring shaft 211 passes through the upper cover 11 of the kettle and is connected to auxiliary equipment such as the stirring drive motor. The lower end of the stirring shaft 211 is fixed to the bottom head of the kettle through a rotating bearing. The connection between the stirring shaft 211 and the driving equipment can adopt any existing mature technology. The paddles of each level are arranged at equal intervals along the stirring shaft 211 and are evenly distributed around the circumference. The stirring shaft 211 has a diameter of 100 mm, and a hollow structure below the bottom paddle, with an inner diameter of 40 mm and a wall thickness of 4 mm. The bottom paddle blades are also hollow structures, with a tubular cavity with an inner diameter of 12 mm in the middle, and the two are interconnected. The hollow structure of the stirring shaft 211 is connected to the pipeline outside the kettle through a DN20 pipeline, and a heat transfer medium (such as heat transfer oil, etc.) can be placed in the stirring shaft 211 and the blades. The bottom paddle of the stirring paddle 212 adopts a blade with a radial flow type (such as a turbine paddle of a semi-elliptical tube), and the paddles of each level except the bottom paddle adopt an axial flow type blade (such as an axial flow wide-blade wing-shaped paddle), and a downward pressure operation mode is adopted.

[0101] The heat exchange tube 24 is a single spiral tube structure with a tube diameter of DN12. The baffle 22 is rectangular, 400 mm long, 35 mm wide, and 10 mm thick, with 6 pieces in number, and one side of the rectangle is connected to the kettle wall surface. The baffle 22 is vertically connected to the axial angle of the stirring shaft 211 at 0°, and is connected to the jacket through a pipe passing through the kettle wall, and a heat transfer medium can be placed in the hollow structure.

[0102] (2) Method for copolymerization of ethylene and methyl acrylate

[0103] Using alkyl salicylaldehyde imine late transition metal complex or alkyl diimine late transition metal complex as catalyst precursor, alkyl aluminum compound and / or organic boron compound as activator, and at least one of toluene, hexane, etc. as solvent, the copolymerization of ethylene and polar monomer, especially the copolymerization of ethylene and methyl acrylate, is completed under the conditions of 1.0-10.0MPa, 30-100°C, and 0.5-8h. The reactor is replaced with 0.1MPa nitrogen three times to exhaust the air in the reactor. The reactor is heated to 150°C under a vacuum degree of -0.1MPa, kept at a constant temperature for 2h, and then cooled to room temperature. The reactor is replaced with 0.1MPa nitrogen three times again, and then the reactor is pressurized to 0.1MPa with 0.1MPa ethylene and replaced three times. At room temperature and in an ethylene atmosphere, the measured solid and liquid materials such as catalyst, solvent and polar monomer are added to the reactor through the liquid material feed pipe 111 on the upper cover of the reactor, and the filling coefficient of the reactor is maintained at 0.6. Start the stirring paddle 212, and make the reactor reach the set reaction temperature through the hot medium in the outer jacket of the reactor body 12. The reaction temperature is controlled to be constant within the desired range by adjusting the flow rate of the cold medium in the heat exchange tube 24 in the reactor online. The temperature is monitored by the temperature measuring facilities inside the reactor and the required signal of the temperature controller is fed back. The temperature control accuracy is ±1°C. Ethylene is introduced to make the reactor reach the set reaction pressure and keep the pressure of the reactor constant. The instantaneous consumption flow rate and cumulative consumption flow rate of ethylene are measured by a mass flowmeter. After the reaction reaches the set time, stop stirring and release the ethylene pressure until the pressure gauge shows 0MPa. Add a terminator (such as alkyl alcohol) in an amount of 0.01% of the filling liquid volume to terminate the reaction. The reaction materials are discharged from the reactor through the liquid discharge port of the lower head of the reactor body 12 to complete the subsequent work such as solid-liquid separation, polymer devolatilization, drying, weighing and analysis.

[0104] Source of raw materials and equipment: Ethylene, polymerization grade, purity 99.9%, produced by Daqing Branch of China National Petroleum Corporation.

[0105] Methyl acrylate, analytical grade, 98.5%, containing 0.05% MEHQ stabilizer, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0106] Methyl methacrylate, analytical grade, 98.5%, containing 0.05% MEHQ stabilizer, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0107] Toluene solution of methylaluminoxane, concentration 10%, provided by Huainan Kedi Chemical Technology Co., Ltd.

[0108] Toluene, analytical grade, 99.5%, was provided by Nanjing Chemical Reagent Co., Ltd.

[0109] Hexane, 98%, provided by Fushun Branch of PetroChina Co., Ltd.

[0110] Experimental results: The results of copolymerization of ethylene and methyl methacrylate show that the sticking rate of the kettle is ≤5%, the heat transfer surplus can reach 200%, and the viscosity of the reaction system can meet the need of regulation between 0 and 1000 cP.

[0111] Example 2

[0112] 2m 3 Ethylene polar copolymerization reactor.

[0113] A kettle-type stirred reactor, comprising a cylinder 1 and an internal component 2, the inner volume of the reactor is 2m 3 , material 304.

[0114] The cylinder 1 is composed of an upper cover 11 and a kettle body 12. The upper cover 11 is a solid body with a circular head, a diameter of 1300mm, and a curved surface height of 325mm. The kettle body 12 is composed of three parts: the kettle body 12, the lower circular head 122, and the outer jacket. The cylindrical hollow body has a length of 1500mm, an external diameter of 1300mm, and a wall thickness of 15mm. The kettle body 12 is provided with a cold medium inlet and outlet pipe port 243 and a hot medium inlet and outlet pipe port 244 connected to the heat exchanger in the kettle, and the pipe diameters are both DN40. The lower circular head 122 has a diameter of 1300mm, a curved surface height of 325mm, and is provided with a liquid material discharge pipe 1221 with a pipe diameter of DN102. The jacket has a diameter of 1500mm and is provided with a cold medium inlet and outlet pipe port 1231 and a hot medium inlet and outlet pipe port 1232, both of which have a diameter of DN40. A heat conduction medium (such as an electric heating plate) is provided on the outer wall of the inner kettle of the jacket. In addition, 8 mounting lugs are provided. The upper cover 11 of the kettle is provided with a liquid material feed pipe 111, with a diameter of DN102. The upper cover 11 of the kettle is provided with a gas material feed pipe 112, with a diameter of DN40. The upper cover 11 of the kettle is provided with a vent pipe, with a diameter of DN40. The kettle body 12 is provided with 6 thermocouple tubes 13 containing temperature measuring thermocouples, with a diameter of DN14, a length of 500mm and extending deep into the kettle.

[0115] The internal component 2 is composed of a stirring device, a heat exchange tube 24 , a guide tube 21 , a baffle 22 and a gas distributor 25 .

[0116] The stirring device is composed of a stirring shaft 211, a stirring paddle 212 and auxiliary equipment (such as a stirring motor 213). The stirring paddle 212 is a three-stage composite paddle consisting of a bottom paddle, a first-stage paddle and a second-stage paddle. The bottom paddle has a diameter of 580 mm, and the first-stage upper paddle and the second-stage upper paddle have a diameter of 600 mm, with a spacing of 300 mm. The stirring shaft 211 is located on the line connecting the center of the upper cover 11 and the center of the head of the kettle body 12. The upper end of the stirring shaft 211 passes through the upper cover 11 of the kettle and is connected to auxiliary equipment such as a stirring drive motor. The lower end of the stirring shaft 211 is fixed to the bottom head of the kettle through a rotating bearing. The connection between the stirring shaft 211 and the drive equipment can adopt any existing mature technology. The stirring paddle 212 is located in the guide tube 21. The blades of each level are arranged at equal intervals along the stirring shaft 211 and are evenly distributed around the circumference, and the edge of the blade has a gap of ≥5 mm with the inner wall of the guide tube 21. The diameter of the stirring shaft 211 is 200mm. The stirring shaft 211 has a hollow structure below the bottom paddle, and is provided with a hollow tube with an inner diameter of 40mm. The bottom paddle blade is also a hollow structure, and the middle is a tubular cavity with an inner diameter of 20mm. According to needs, the tubular cavity is composed of a main pipe and a branch pipe to form a closed loop. The hollow tube of the stirring shaft 211 is connected to the tubular cavity of the blade, and the hollow tube of the stirring shaft 211 is connected to the pipeline outside the kettle through a DN40 pipeline. A heat transfer medium (such as an electric heating plate, heat transfer oil, etc.) can be placed in the stirring shaft 211 and the blade. The bottom paddle of the stirring paddle 212 adopts a blade with a radial flow type (such as a turbine paddle of a semi-elliptical tube), and the paddles of each level except the bottom paddle adopt an axial flow type blade (such as an axial flow wide-leaf wing-shaped paddle), and a downward pressure operation mode is adopted.

[0117] The heat exchange tube 24 is a combined tube bundle structure, consisting of two main pipes entering and exiting the reactor body 12. The main pipe diameter is DN40. The two main pipes are further divided into 4 groups of branch pipes. The branch pipe diameter is DN16. The branch pipes are spirally coiled in the reactor for 6 turns. The heat exchange tube 24 is located between the guide tube 21 and the inner wall of the reactor body 12.

[0118] The guide tube 21 is a cylindrical solid structure with a certain thickness. In particular, the guide tube 21 is a trapezoidal cylindrical structure with a lower opening larger than an upper opening, and the angle formed between the trapezoidal side and the axis of the stirring shaft 211 is 5°, the upper diameter is 620mm, the lower diameter is 640mm, and the length is 1500mm. Five inner baffles 23 are arranged on the inner wall of the guide tube 21. The inner baffles 23 are rectangular structures with dimensions of 1500mm×20mm×10mm, and are 5° counterclockwise with the axial direction of the stirring shaft 211. The inner baffles 23 are arranged in a continuous manner and the width at the blade of the stirring paddle 212 is not greater than the gap between the blade and the inner wall of the guide tube 21.

[0119] The baffle 22 is a rectangular structure with a certain thickness, with a size of 1500mm×50mm×25mm, and one side of the rectangle is connected to the wall of the kettle. In addition, the baffle 22 also serves as a support for the heat exchange tube 24. The baffle 22 is a rectangular structure with a trapezoidal cross section and a hollow interior, which is 10° clockwise with the axial direction of the stirring shaft 211, and is connected to the jacket through a pipeline passing through the kettle wall. The cold or hot medium in the jacket can be introduced into the hollow structure of the baffle 22 through the pipeline to form a closed loop.

[0120] The gas distributor 25 is introduced into the kettle through the head below the kettle body 12, and is composed of three straight pipes introduced into the kettle and a pipe end distribution head 251, with a pipe diameter of DN25, and is located below the heat exchange tube 24. The pipe end distribution head 251 of the gas distributor 25 is linear and is on the same horizontal line as the bottom propeller, and the angle between the pipe end distribution head 251 and the horizontal edge of the bottom propeller blade is 0°.

[0121] The experimental results of cold model and other tests show that the reactor can meet the requirements of ethylene and methyl acrylate copolymerization with a sticking rate of ≤3%, a heat removal surplus of ≥150%, and a reaction system viscosity that can be adjusted between 0-5000cP.

[0122] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An ethylene polar copolymerization reactor, characterized in that: The copolymerization reactor comprises: The cylinder body comprises an upper cover and a kettle body, and the kettle body consists of an upper cylindrical hollow body, a lower circular head and an external jacket; and an internal component disposed in the cylinder, the internal component comprising a flow guide cylinder and a stirring device located in the flow guide cylinder; The stirring device comprises a stirring shaft, a stirring paddle and a stirring motor, wherein the stirring paddle is a composite paddle consisting of a bottom paddle and a plurality of non-bottom paddles or upper paddles, the stirring paddle is mounted on the stirring shaft, the upper end of the stirring shaft passes through the upper cover and is connected to the stirring motor, and the lower end of the stirring shaft is fixed to the lower circular head through a rotating bearing; Among them, the stirring shaft has a hollow structure below the bottom paddle, and the blades of the bottom paddle are also hollow structures, and the two are connected to each other. The hollow structure of the stirring shaft is connected to the external pipe of the kettle body through a pipe, and a heat conduction medium is placed in the stirring shaft and the blades.

2. The ethylene polar copolymerization reactor according to claim 1, characterized in that: The stirring shaft is located on the line connecting the center of the upper cover and the center of the kettle head; The blades of each level are arranged at equal intervals along the stirring shaft and are evenly distributed around the circumference, and there is a certain gap between the edge of the blade and the guide tube; The bottom paddle of the stirring paddle adopts a radial flow type blade, and the paddles of each stage except the bottom paddle adopt axial flow type blades.

3. The ethylene polar copolymerization reactor according to claim 1, characterized in that: The inner component also includes a baffle, one side of which is connected to the wall of the kettle body. The baffle is a hollow structure. The baffle and the external jacket are connected to each other through a pipeline on the wall of the kettle body, and a heat transfer medium is placed in the hollow structure.

4. The ethylene polar copolymerization reactor according to claim 3, characterized in that: The baffle is a rectangular structure with a trapezoidal cross section and a hollow interior, and forms an angle of 0-10° clockwise with the axial direction of the stirring shaft.

5. The ethylene polar copolymerization reactor according to claim 1, characterized in that: A plurality of inner baffles are arranged on the inner wall of the guide tube. The inner baffles are rectangular structures, forming a counterclockwise angle of 0-5° with the stirring shaft, and the length does not exceed the upper and lower edges of the guide tube. The inner baffles are arranged continuously and the width at the stirring paddle blades is not greater than the gap between the blades and the inner wall of the guide tube.

6. The ethylene polar copolymerization reactor according to claim 1, characterized in that: The guide tube is a cylindrical solid structure with a certain thickness. The guide tube is a trapezoidal cylindrical structure with a lower opening larger than an upper opening. The angle formed by the trapezoidal side and the axis of the stirring shaft is 0-5°.

7. The ethylene polar copolymerization reactor according to claim 3, characterized in that: The internal component further comprises a heat exchange tube, and the heat exchange tube is located between the guide tube and the kettle body, and the baffle can serve as a support for the heat exchange tube.

8. The ethylene polar copolymerization reactor according to claim 7, characterized in that: The heat exchange tube is a combined tube bundle structure, which consists of a first main pipe and a second main pipe entering and exiting the reactor body. The first main pipe and the second main pipe are further divided into multiple groups of branch pipes, and the branch pipes are spirally coiled in the reactor body.

9. The ethylene polar copolymerization reactor according to claim 7, characterized in that: The internal component also includes a gas distributor, which is located below the heat exchange tube. The gas distributor is introduced into the kettle body through the lower circular head of the kettle body. The gas distributor includes a plurality of straight tubes introduced into the kettle and a tube end distribution head; The pipe end distribution head of the gas distributor is linear and is on the same horizontal line as the bottom propeller, and the angle between the distribution head and the horizontal edge of the bottom propeller blade is 0-5°.

10. The ethylene polar copolymerization reactor according to claim 7, characterized in that: The kettle body is provided with cold medium inlet and outlet pipes and hot medium inlet and outlet pipes connected to the heat exchange tube; the lower circular head is provided with a liquid material discharge pipe; The outer jacket is provided with a cold medium inlet and outlet pipe opening and a hot medium inlet and outlet pipe opening, and a heat transfer medium is provided on the outer wall of the inner kettle of the outer jacket; The upper cover is provided with a liquid material feed pipe, a gas material feed pipe and a vent pipe; the kettle body is also provided with a plurality of thermocouple tubes for containing temperature measuring thermocouples.

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